Electric controlling apparatus



Jul 14, 1936. LQGAN' 7 2,047,915-

ELECTRI C CONTROLLING APPARATUS Filed Sept. 1'7, 1931 INVIIENTOR Au. ATTORNEY Patented July 14, 1936 nmo'rmo COhlTROLLING APPARATUS Frank G. Logan, Mount Vernon, N. Y., assignor to Ward Leonard Electric Company, a corporation of New York Application September 17, 1931, Serial No. 563,351

21 Claim.

cuit passing through two alternating current jwindings on the two outer legs and a controlling direct current passing through a winding on the middle leg. Other forms of reactors have been I proposed, but all of them have the-objection that if made to give in themselves a complete range of control from approximately maximum voltage of the supply circuit to a complete black-out of the 4 5 lamps, the cost of the reactor runs ,very high.

Another difiiculty is that by its very nature, as

regards form of construction, the cost is high, even for moderate limits of control, as compared with simple forms of core and windings, such as the usual transformer construction.

One object of the present invention is to combine auxiliary controlling means with such reactors so as to permit the reactors to be made smaller as regards core and windings and cost of the same. Another object is to increase the range of control obtained, while at the same time keeping the total cost low. The auxiliary controlling means is of a form that may be conveniently and economically manufactured. Its comparatively low cost and its advantageous coaction with the main reactor gives improved controlling results over a .wide range in an economical manner. Other objects and advantages will be understood from the following description and accompanying drawing.

The drawing is adiagram showing one embodiment of the invention. 4

The usual form of reactor is shown as having a core I of the three-legged type having the alternating current windings 2 on the-outside legs in series with one of the supply lines from the alternating current source 3 and in series with the load 4. The middle leg is provided with a winding 5 excited by direct, or any uni-directional, current, a source of direct current 6 being indicated as having a variable means I for controlling the current in the winding 5. Any desired unidirectional source or meansfor controlling the current in the winding 5 may be used.

. One feature of the invention relates to the provision of auxiliary means for boosting the voltage derived from the reactor under conditions Iwhen the boosting effect is desirable. This comprises a transformer having a core 8, a primary winding 8a and a secondary winding 8b. This transformer is indicated as of the core type, but may be of the shell type, or other form. The current through the primary winding to may be adjusted by an adjustable resistance 9, or by taps into the winding 8a, or by any other suitable means. The primary winding 8a has its terminals connected across the load 4; and the secondary winding 8b is in series with the windings 2 and the load. 1

Another feature of the invention involves the provision of auxiliary bucking means which is shown as a transformer having a core in, a primary winding Illa and a secondary winding lflb. The primary winding has its terminals connected across the windings 2 of the reactor and provision may be made for adjusting the current of the winding Illa as by means of an adjustable resistance II, or any other suitable means. The secondary Hlb is shown connected in series with the return line of the load circuit to the alternating 20 current source '3.

As regards the operation and coactionof the different parts, letit be assumed that the current in the winding 5 has been controlled to be at maximum value. At that time the reactance of the reactor is at a minimum, the core being saturated. The reactive effect of the alternating current windings 2 is at its minimum and, as far as the reactor is concerned, the load 4, shown as a lamp load, receives maximum voltage. Under these conditions the boosting transformer 8 serves to increase the voltage applied to the load over and above that which would be obtained from use of the reactor alone. This is because the primary winding So. then receives the maximum voltage acrossits terminals, being subjected to the maximum voltage of the load; and also because the voltage of the secondary 8b is in phase with, or approximately in phase with, the line voltage and is connected in a direction to be additive to the line voltage. At this time, the voltage applied to the primary Illa of the bucking transformer is at a minimum, being subjected only to the voltage drop across the alternating current windings 2. Thus the secondary winding lllb which is con- 5 nected to oppose the line voltage, has little or no opposing effect.

When the current in the controlling winding 5 of the reactor has been controlled to have its minimum value, the reactance of the reactor is at a maximum and the counter electro-motive force of the windings 2 has its full effect in reducing the voltage applied to the load 'At this time the bucking transformer has full effect in additionally reducing the'voltage applied to the 5 1 load, because the primary winding Ma is then subjected to the full voltage across the windings 2, and thereby causes the secondary lllb to have maximum effect in opposing the line voltage. The effect of this bucking transformer is, therefore, to cause the voltage applied to the load 4 to be reduced more than would result from use of the reactor alone. transformer has little or no effect in boosting the voltage applied to the load, because its primary is subjected to the very low voltage of the load with the result that the additive voltage due to the secondary winding 8b would be comparatively small. A further action occurs with reference to the boosting transformer under low voltage conditions, due to the fact that the reactor current, under low load voltage conditions, is out of phase or approaching 90, with the reactor voltage. boosting transformer at this time carries current in phase with the voltage, because it is in shunt to the lamp load circuit which has no appreciable inductance. Consequently, the voltage of the secondary 8b of the boosting transformer is at this time 90 out of phase, or approaching 90 out of phase, with the reactor voltage with the result that, even though the voltage of the secondary winding 8b is small, it is nevertheless quite considerably out of phase with the reactor voltage and consequently does not exert any material boosting eifect.

Thus it is apparent that when it is most desirable to have the boosting transformer effective in boosting the voltage applied to the load, it is fully active and cooperative with the reactor at that time; and when the conditions are Y such that the boosting effect is undesirable, the boosting transformer then has no material boosting effect. Similarly, when it is desirable to have the bucking transformer cooperate with the reactor in further reducing the voltage applied to the load, it then has maximum bucking effect; but when it is undesirable to have the bucking transformer oppose the voltage applied to the load, then the conditions are such that the bucking transformer has no material opposing efiect.

In some cases it may be desirable to use the boosting means in its cooperation with the reactor without the bucking means, such as where the higher range of voltage and current is desirable and the extreme lower range unnecessary, in which case the boosting means could be used without the bucking means. Similarly, the bucking means may be used in cooperation with the reactor without the presence of the boosting means. But for the purpose of obtaining a high and low range of control, both the boosting and bucking means are very desirable in cooperation with the reactor and with each other.

It will be understood that for simplicity, the number of turns in the different windings are not attempted to be indicated and that these may be varied and adjusted with reference to each other and to the reactor to suit the desired conditions, according to well understood principles of design. It will also be understood that although a simple form of reactor has been indicated, the invention is applicable to other forms of reactor. Likewise, although the core type of boosting and bucking transformers is indicated in the drawing, they may be of the At this time the boostingv But the primary 8a of the' l. The combination of an altemating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying the reactance of the reactor, and a device for bucking the voltage applied to the consumption circuit, said device having an element affected by variations in voltage across the terminals of said alternating current winding.

2. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying the reactance of the reactor, and a device for bucking the voltage applied to the consumption circuit, said device having a controlling winding affected by variations in voltage across the terminals of said alternating current winding.

3. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying the reactance of the reactor, and a transformer for bucking the voltage applied to the consumption circuit, said transformer having a primary winding affected by variations in voltage across the terminals of said alternating current winding.

4. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying 3 the reactance of the reactor, and a transformer for bucking the voltage applied to the consumption circuit, said transformer having a primary winding affected by variations in voltage across the terminals of said alternating current winding and having a secondary winding in series in the consumption circuit.

5. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying the reactance of the reactor, a device for boosting the voltage applied to the consumption circuit, said device having an element affected by variations in voltage applied to the consumption circuit, and a second device for bucking the voltage applied to the consumption circuit, said second device having an element aifected by variations in voltage across the terminals of said alternating current winding.

6. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying the reactance of the reactor, a device for boosting the voltage applied to the consumption circuit, said device having a controlling winding affected by variations in voltage applied to the consumption circuit, and a second device for bucking the voltage applied to the consumption circuit, said secand having a controlling winding for varying the reactance of the reactor, a transformer for boosting the voltage applied to the consumption circuit, said transformer having a primary winding l across the terminals of said alternating current winding. l

,8. The combination of an alternating current "source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for varying the reactance of the reactor, a transformer for boosting the voltage applied to the consumption circuit, said transformer having a primary winding afiected by variations in the voltage applied to the consumption circuit and having a secondary I winding in series in the consumption circuit,

1 and a second transformer for bucking the voltage applied to the consumption circuit, said second transformer having a p a windin f t d by variations in voltage across the terminals of said alternating current winding and having a secondary winding in series in the consumption circuit.

9. The combination of an alternating current I source, a reactor having an alternating current winding in series with the consumption circuit 1. and having a controlling winding, manual means for adjusting the current in said winding to change the reactance of the reactor for adjusting the voltage applied to the consumption circuit to a desired value over a certain range, and 1 a: device forboosting the voltage applied to the consumption circuit upon increase of said voltage, said device having an element directly con- 'nected across theload circuit and directly responsive to changes in voltage applied to the load.

10. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding, manual means for adjusting the current in said winding to change the reactance of the reactor for adjusting the voltage applied to the consumption circuit to a desired value over a certain range, and a device for boosting the voltage applied to the' consumption circuit upon increase of said Voltage, said device having a controlling winding directly .connected across the load circuit and directly responsive to changes in voltage applied to the load. I

11. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit I and having a controlling winding, manual means for adjusting the current in said winding to 1 change the reactance of the reactor for adjusting the voltage applied to the consumption circuit to a desired value over a certain range, and a transformer for boosting the voltage applied to v the consumption circuit, said transformer having a primary winding directly connected across the change the reactance of the reactor for adjusting the voltage applied to the consumption circuit to a desired value over a certain range, and a.

transformer for boostingthe voltage applied to the consumption circuit, said transformer having a primary winding directly connected across the load circuit and directly responsive to changes in voltage applied to the load and having a secondary winding in series in the consumption circuit.

13. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding for waiving the reactance of the reactor, and a transformer for'bucking the voltage applied to the consumption circuit, said transformer having a primary winding directly connected across the terminals of said alternating current winding and having a secondary winding in series in the consumption circuit.

14. The combination of an alternating current source, a reactor having an alternating current winding in series with the consumption circuit and having a controlling winding, manual means for adjusting the current in said winding to change the reactance of the reactor for adjusting the voltage applied to the consumption circuit to a desired value over a certain range, a transformer for boosting the voltage applied to the consumption circuit upon increase of said voltage, said transformer having a primary winding directly connected across the load. circuit and directly responsive to changes in voltage applied to the load circuit and having a secondary winding in series in the consumptionflcircuit, and a second-transformer for bucking the voltage applied to the consumption circuit upon decrease of said voltage, said second transformer'having a primary winding directly connected across the terminals of said alternating current winding and having a secondary winding in series in the consumption circuit.

15. In combination, an alternating current supply circuit, a load connected thereto, a saturable reactor connected in series with said load, and a booster transformer having a secondary winding connected in series with said load and a primary winding connected in parallel with said load.

'16. In combination, an alternating current supply circuit, a load connected thereto, a saturable reactor having a winding connected in series with the load, and a bucking transformer having a secondary winding connected in series with the load and a primary winding connected in parallel for said reactor, means for controlling the ener- I gization of said control winding, a bucking transformer having a voltage bucking secondary winding connected in said circuit, a-primary winding 'for said transformer, and connecting means for energizing said primary winding from said circuit with a voltage which varies substantially directly with the voltage drop across the alternating current winding of said reactor.

18. An illumination control system comprising, in combination, an alternating current supply circuit, a plurality of electric lamps connected therein, a saturable core reactor having an alternating current winding connected in said circuit,

' a direct current control winding for said reactor,

means for varying the energization of said control winding so as to vary the voltage applied to said lamps, a bucking transformer having a secondary winding connected in series with said lamps, a primary winding on said booster transformer, and connecting means for energizing the primary winding of said booster transformer from said circuit with a variable voltage which varies substantially inversely with the voltage applied to said lamps.

19. A compensated electric lamp dimming system comprising, in combination a source of alternating current, a plurality of electric lamps connected thereto, a saturable core reactor having an alternating current winding connected in series with said lamps, a direct current control winding for said reactor, means for varying the energization of said control winding whereby the saturation of said reactor and consequently the voltage applied to said lamps is controlled, a bucking transformer having a voltage bucking winding connected in series with said lamps, a primary winding for said transformer, and means connecting said primary winding to be energized from the circuit which includes said lamps with a variable voltage which is a minimum when the saturation of said reactor and the voltage across said lamps are a marimum and which is a maxi mum when the saturation of said reactor and the voltage across said lamps is a minimum.

20. In combination, an alternating current circuit, a load connected thereto, a saturable reactor having a winding/connected in series with the load, means for varying the reactance of said reactor, and means comprising a transformer for 1 inserting a voltage in said circuit in opposition to the voltage of said circuit, said opposing voltage varying directly with the reactance of said reactor.

21. In combination, an alternating current circuit, a load connected thereto, a variable impedance device having a winding connected in series with the load to control the current flow therein, and means comprising a transformer for inserting a voltage in said circuit in opposition to the voltage of said circuit, said opposing voltage 20 varying directly with the impedance of said device.

FRANK G. IOGAN. 

